Tuesday, September 29, 2009

Google Checkout is making PayPal look good

This post is definitely off-topic for my blog, but I am extremely disappointed with Google Checkout's Merchant services, and I want to publicize the difficulty.

I have a customer that placed an order on my website and paid with Google Checkout. Her credit card was listed as "declined", so she called her credit card company to find out why. The credit card company responded that they had no record of the Google Checkout transaction at all, and there were no declined transactions on the account.

Of course, Google Checkout has no support phone number. Apparently they recently removed their support email address and online support contact form.

UPDATE: I found the "contact us" link at the bottom of the page, which allows merchants to enter an order number and request assistance, but there is no text entry box to actually describe the exact problem.



So now I am stuck with a very frustrated customer and perhaps a lost order. Worse, I have no way of fixing the situation because Google Checkout has no way of being contacted with details about the problem. Thanks, Google.


Here's some links to others who have had problems all stemming from the complete lack of merchant support.

http://www.shaftek.org/blog/2009/03/04/contact-phone-number-for-google-checkout/

http://www.google.com/support/forum/p/checkout-merchants/thread?tid=1c4ddc2e27f4ec72&hl=en

http://news.zdnet.com/2100-9595_22-341375.html

http://www.google.com/support/forum/p/checkout-merchants/thread?tid=67e6e5c02c6f3233&hl=en

Thursday, September 24, 2009

Telescope magnification

A friend recently asked me about telescopes, and it made me think about the pictures that I took with my telescope which I haven't looked at in years. This series of photos was a test of the range of magnifications possible with a couple camera lenses and the telescope.

These photos were shot with a Nikon FE2, with some run-of-the-mill 400ASA color film. The photos were developed and printed 4x6 at a 1-hour photo place. I scanned the photos with a flatbed scanner.

50mm Nikon lens. This is essentially the field of view that normal human vision has.

135mm Vivitar lens.

2032mm Celestron Nextar 8" SCT telescope. Prime focus. The ceramic insulator is just visible in the lower right corner.

The same telescope using eyepiece projection -- I forget the focal length of the eyepiece. The white halo in the center of the image is an artifact of my shoddily-mounted eyepiece setup.

A shorter focal length eyepiece increases the magnification even more. This is probably a 6mm eyepiece, giving 2032/6 = 338x magnification. The photo is blurry, but this is mainly due to tiny vibrations in the 'scope and camera. When viewing this directly through the eyepiece, the image is pretty sharp since human eyes and brains have better image processing than cameras.

Tuesday, September 22, 2009

Stainless steel conical beer fermenter Pt.3

I just finished welding together the stainles racking cane for the beer fermenter project.

Even though this may not look like much, I am quite proud. It is a 5/8" dia stainless tube, but the wall thickness is only .020". I sliced it on my new metal band saw, reoriented the pieces to make an elbow, then tacked it in two places, and welded all the way around. It's air-tight. The trick is to get the tacks done really quickly. I only used filler (.035") to make the tacks, then just fusion welded it in very short sections (a few seconds at a time). I blew through it once, and had to repair it with filler.

Here's the tube welded to a tri-clamp plate, which is welded to one side of a three-piece ball valve.

Here's the other side of the ball valve welded to a hose barb.

The complete assembly is attached to the tri-clamp port on the side of the tank. The purpose of all this hardware is to be able to rotate the racking cane while draining beer from the tank. Thus, the height at which the beer is drawn can be adjusted. This allows the maximum amount of clear beer to be drawn from the tank without getting any cloudy beer that has settled to the bottom.

Inside the tank.

Stainless steel conical beer fermenter Pt.2

The next step in the beer fermenter project is to mount some copper blocks to the outside of the stainless tank. The purpose of these blocks will be to thermally couple two peltier devices to the surface of the tank. The tank is cylindrical (near the top) and the peltiers are flat, so the copper blocks must be curved on one face, and flat on the other. I started by cutting off some chunks of copper and milling the edges square.



Next, I used a long end mill to profile the sides with a radius that matches the outside of the stainless tank. My plan was to silver solder the copper blocks to the stainless tank exterior. This turned out to be a very bad idea. I started by fluxing the copper and stainless, then separately covering them with a thin layer of silver solder. No problem yet. I put the semi-cooled block onto the tank, and planned to heat the tank and block and let the two solder-covered surfaces melt together. This started working, but then the stainless expanded dramatically under the block. The copper was lifted a clear 1/4" off the surface near the edges, while the center was making contact. I removed the heat, and looked inside the tank to find this new disaster:

A monster crack had developed in the wall of the tank! I am still not sure why this happened. It obviously has something to do with the metals' differing rates of expansion, but I had no idea the consequences could be so damaging. Perhaps this has something to do with the stresses in the metal from the spinning (cone-forming) operation?

Luckily it wasn't too difficult to repair the crack. Since the crack went clear through the tank wall, I had to fight the silver solder which was molten and trying to flow into the weld puddle. The copper blocks must be making good thermal contact, since I maxed my TIG machine out at 200A, and it was just enough to comfortably weld.

There are two copper blocks (each made of two pieces of bar). In order to avoid the silver-soldering nightmare again, I used silver epoxy to join the copper to the tank. After both blocks were attached, I mounted the assembly in the milling machine, and flattened the faces.

If I were going to do this again, I would profile the copper backside, flatten the face, then use silver epoxy to attach it to the tank.

UPDATE: This method did NOT work. I was not able to hold the glass without rocking it very slightly. This created a very smooth, but curved surface on the copper. It was unsuitable to mount the peltier.

Here, I am removing the milling marks with sandpaper mounted on a 1/4" thick glass plate. This took a very long time. In fact, I am still "going up through the grits" right now. The next step will be to weld a small threaded boss on either side of the copper blocks. This will serve as an attachment point for the peltier heatsink. The peltier itself will be pinched between the copper and the heatsink.

Thursday, September 17, 2009

Three-way flow regulator for argon shielding gas

The serious TIG welders have two flow regulators on their argon supply -- one for the torch, and the other for the purge argon on the backside of the weld. I found some cheap flow regulators on eBay, and I made a manifold for the two I bought plus the original regulator. I've imagined situations where three regulators might be helpful like welding a gusset on the outside of a tank. The gusset would need backing gas in addition to the torch side, and the inside of the tank would need to be purged as well. Who knows.
I made the manifold itself out of a block of white Delrin with four 1/4-18 pipe threads cut into it. The original regulator (on the left) has 1/4-18 straight threads. I just ran my tap really deep into the Delrin so that the regulator would fit in. It's very easy to make metal fittings seal with Delrin and no Telfon tape is necessary. The Chinese argon pressure regulator also had a 1/4-18 female straight thread which was intended to seal on the end of the pipe. A regular 1/4" brass pipe thread nipple worked just fine and presumably bottomed out and sealed on its end.